This goal of this SBIR project is to quantify and validate the feasibility and potential for a non- obtrusive, wearable, in-shoe gait-monitoring device for children with Cerebral Palsy (CP). It is hypothesized that continuous monitoring and analysis of simple gait parameters in children with CP outside the clinical laboratory and during normal daily activities will provide clinically useful outcomes data that are not currently available and critical diagnostic data for determining intervention timing. There is a clinical need for objective, quantitative data to assess the severity of toe walking and its progression over time as the child develops and intervention strategies are implemented to improve his/her mobility. Also, extending such assessment to the home and community settings is critical in order to allow clinicians to evaluate whether clinical interventions are effective in improving mobility outside of the clinic and overall the quality of life of the child. The key innovation is the development of a miniature extremely low-power data acquisition/recording device, which can be worn non-obtrusively by children with CP during activities of daily living (ADL's) to measure ankle angle and center of pressure trajectories during ambulation. In Phase I, hardware/software development and validation will be followed by a pilot study of children with CP to compare measured in-shoe gait parameters against gold- standard laboratory kinematic and kinetic data. Data clustering techniques will be employed to determine the feasibility of classifying these motor tasks from the in-shoe monitoring data alone, and to identify different ambulatory activities (i.e. level walking, ramp ascending and descending, and stair ascending and descending). In Phase II, the hardware is incorporated into the sole of a sneaker, a multi-stage classifier is developed and validated, and a pilot longitudinal study is performed to evaluate the development of a novel Toe Walking Severity (TWS) index. The long-term goal of this research and development project is to address clinical problems associated with objective quantification of gait abnormalities and the success of clinical interventions by developing low cost, readily available in-shoe monitoring tools and analysis methods to quantify longitudinally the severity of toe walking outside the clinic environment. If successful, the proposed technology carries significant potential for monitoring gait in patients affected by other pathologies in which gait parameters are expected to change over time as a function of the progression of the disease (e.g. shuffling in patients with Parkinson's disease, progressive loss of ankle control in patients with multiple sclerosis). The proposed ActiveGait device provides the enabling technology to continuously monitor toe walking at home. Outcome measures quantifying the success and timing of clinical interventions for toe walking will be developed based on extremely large data gathered from the individual's walking at home and over long periods of time. If technically and economically feasible, the additional up-front cost of the monitoring system in the shoe will be far outweighed by reduced health care costs associated with treatment and rehabilitation for toe walking.